Increase in expression level of p21sdi1/cip1/waf1 with increasing division age in both normal and SV40-transformed human fibroblasts

Oncogene. 1995 Mar 2;10(5):835-40.


p21sdi1/cip1/waf1 gene, whose product inhibits Cyclin/Cdk kinase and blocks cell proliferation, is known to be up-regulated by p53 and to be expressed at high levels in senescent human fibroblasts. The present paper reports that p21 expression level was much lower in SV40tsT-antigen transformed cells than in normal cells and that after inactivation of tsT-antigen it recovered to that of normal cells. However, cell division age-dependent increase in expression level of p21 occurred not only in normal human fibroblasts but also in SV40tsT-antigen transformed fibroblasts with active T-antigen. These results suggest that cell age-dependent increase in p21 occurs independently upon the function of T-antigen binding proteins including p53, while the basal expression level of p21 is up-regulated by p53 as previously reported.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, Polyomavirus Transforming / physiology
  • Cell Line, Transformed
  • Cell Transformation, Neoplastic / metabolism*
  • Cellular Senescence
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins / analysis
  • Cyclins / genetics*
  • DNA / biosynthesis
  • Fibroblasts / metabolism
  • Gene Expression Regulation*
  • Humans
  • Protein Kinase Inhibitors*
  • Simian virus 40 / immunology
  • Temperature
  • Tumor Suppressor Protein p53 / analysis


  • Antigens, Polyomavirus Transforming
  • CDKN1A protein, human
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins
  • Protein Kinase Inhibitors
  • Tumor Suppressor Protein p53
  • DNA